Bult-Schlenken-Plateau – Teil 1: Vegetationswandel im Rhythmus periodisch wechselnder Niederschlagsmengen

– Change in Plant-Species following Patterns of Precipitation –

Sphag. papillosum und S. fallax bedrängen einen dichten Bestand von Pfeifengras

Sphag. papillosum und S. fallax bedrängen einen dichten Bestand von Pfeifengras (Foto: Gehlken, 2002) am Beginn einer ersten Bult-Entwicklung im Innenraum der Mulde. (Siehe auch: Gehlken, 2002 b)

In a series of pictures we follow the path of development taken by one of the first hummocks showing S. papillosum 2002 to appear  close to the watershed on bed 6n in the middle part (Hummok-Hollow-Plateau) of the area, restituted for reinundation and under our special observation for return of vegetational patterns that finally might initiate peatproductive processes as known from bogs.
The special features of this site turn out to be supportive to sphagnum growth and hummock formation with a high degree of concordance between the shifting amounts of precipitation and varying ratios between hollow-species prevailing during a period of wet years and hummockbuilding sphagna becoming dominant as soon as rainfall declines for some years in a row. Change of dominance among sphagna shows to be accompanied by according turnovers from pipegras to cottongras and back again.
As this lot of only a few squaremeters seems too small to support processes leading towards an endurable acrotelm and peatproduction, the place appears to be especially valuable for studies directed at findings about local (topografical) features, meterological varabilities, and development of vegetation that might lead towards ombrotrophic plant communities.
A very special but nonetheless promising detail leads our attention towards a close connection showing shifting amounts of rainfall (registered close to our site) as highly related to forecasts drawn from what since long time has been known as NAO (North Atlantic Oscillation) and is looked at as a source of periodic shifts between „atlantic/ocenanic“ (i.e. wet & warm) and „continental“ (dry & cold) weather conditions.In this part we focus on shifts to be observed during summer as indicated by growth and distribution of vegetation.
Further observations might disclose that rhythmic changes of more extended wavelength like such well-known phenomena as mire-breathing (Mooratmung) turn out to be triggered by the longterm (in terms of decades) changes between „atlantic“ and „“continental“ conditions as well. There is growing evidence, that the plants specialized on the conditions of coastal rain-mires (e.g. Sphag. papillosum, Erica tetralix) turn out to be well adapted to cope with the rhythmical changes of water supply and its impact on the habitats their community (Erico-Sphagnetum-papillosi) is bound to reconquer. Our next post (Hummock-Hollow-Plateau, Part 2) is planned to cover an area located further down the basins slope focussing at changing habitat conditions as determinated by conditions applied through the winter season.

Feuchter Start im Schlenken-Modus (2002 – 2009)

Feucht- und Trocken-Perioden im Zeitraum der Bultentwicklung

Feucht- und Trocken-Perioden im Zeitraum der Bultentwicklung

Fotofolge und Diagramm der Regenmengen verweisen die bisher gezeigte Entwicklungsreihe in eine Periode mit überdurchschnittlich reichen Niederschlägen, und die merkwürdigen „Einbrüche“ auf dem letztgezeigten Foto von 2009 mögen frühzeitige Anzeichen darauf sein, dass der über Jahre hin überschüssige Regen ausgeblieben ist. Bevor wir diesen Wendepunkt genauer betrachten, eröffnen wir eine Galerie mit Bultfotos der „Trockenjahre“ seit 2009.